Trees deciduous or semi-evergreen. Buds with scales. Leaves petiolate; stipules caducous; leaf blade cordate, papery or leathery, basal veins 5-9, margin minutely denticulate or nearly entire. Flowers unisexual or bisexual (plants polygamo-dioecious or dioecious). Male flowers in cymes. Bracts 2-3, caducous. Pedicel articulate. Sepals 5, valvate, free or shortly connate at base, abaxially stellate puberulent, adaxially sometimes glandular at base. Petals 5, free, imbricate, slightly longer than sepals, clawed. Androgynophore absent. Stamens 25-30; filaments connate at base, in 5 fascicles; anthers oblong, 2-loculed, basifixed, dehiscence longitudinal. Rudimentary ovary enclosed in stamens; style short. Female flowers solitary. Fruit a winged capsule, oblong, loculicidally dehiscent, base shortly stalked, wings 5, thin. Seed 1 per cell, narrowly obovoid.

Four species: China, Myanmar, Thailand; two species (one endemic) in China.